Ralph de la Vega, President and CEO of AT&T’s new Mobile and Business Solutions group, told investors Friday at the Goldman Sachs Communacopia Conference that his company would deploy Wi-Fi Calling at an unspecified point in 2015, “but only as a complement to voice-over-LTE and 3G voice,” as per LightReading.

Apple’s marketing honcho Phil Schiller said Tuesday at the iPhone 6 unveiling that Wi-Fi Calling will be supported at launch by T-Mobile in the United States and UK’s EE, with more carriers flipping the switch on Wi-Fi Calling in due time.

If I were AT&T, I’d go out of my way to roll out Wi-Fi Calling on my network. Some high-end Android handsets already implement this interesting feature that will quickly gain popularity now that the iPhone 6 and iOS 8 support it.

Earlier today, AT&T said that “demand for Apple’s iPhone 6 is already greater than the last two years,” reporting “hundreds of thousands” of pre-orders for the device in just a few hours. An Apple spokesperson also confirmed to Re/code that iPhone 6 demand is already off the charts.

For those unfamiliar with Wi-Fi Calling, it’s a really cool feature which promises to improve audio quality while enabling calling even in pockets of coverage dominated by poor cellular reception.

As the name suggests, Wi-Fi Calling makes calling and text messaging over Wi-Fi, by using your standard cellular connection, possible. So, as you make a call over Wi-Fi (and it’s all automatic, you just make a phone call), you stay on Wi-Fi.

But as you leave the Wi-Fi network, your call will be seamlessly handed off to the normal cell network as the VoLTE call. Wi-Fi Calling uses the ubiquitous Voice over IP (VoIP) protocol to deliver voice communications over IP networks, such as the Internet or your cellular network.

VoIP-based calling over the Internet is supported by Apple’s FaceTime applications, as well as by popular VoIP apps like Skype, Viber and others.

Again, Wi-Fi Calling is now available to T-Mobile customers as a free of charge feature. Sprint has yet to announce support for Wi-Fi Calling on iPhones and Verizon apparently is not interested to undercut its service revenues with this potentially disruptive feature and confirmed ti CNET it had no immediate plans for Wi-Fi Calling.